linux-kernel - Re: [PATCH v5] perf annotate: Fix sample events lost in stdio mode

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Message-ID: <8d9cc941-c85e-34c2-e703-a8d52b615eff@huawei.com>
Date:   Wed, 17 Mar 2021 17:50:26 +0800
From:   Yang Jihong <yangjihong1@...wei.com>
To:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>
CC:     <peterz@...radead.org>, <mingo@...hat.com>, <mark.rutland@....com>,
        <alexander.shishkin@...ux.intel.com>, <jolsa@...hat.com>,
        <yao.jin@...ux.intel.com>, <gustavoars@...nel.org>,
        <mliska@...e.cz>, <linux-kernel@...r.kernel.org>,
        <zhangjinhao2@...wei.com>
Subject: Re: [PATCH v5] perf annotate: Fix sample events lost in stdio mode

Hello,

On 2021/3/16 21:07, Arnaldo Carvalho de Melo wrote:
> Em Tue, Mar 16, 2021 at 10:17:59AM +0800, Yang Jihong escreveu:
>> In hist__find_annotations function, since different hist_entry may point to same
>> symbol, we free notes->src to signal already processed this symbol in stdio mode;
>> when annotate, entry will skipped if notes->src is NULL to avoid repeated output.
>>
>> However, there is a problem, for example, run the following command:
>>
>>   # perf record -e branch-misses -e branch-instructions -a sleep 1
>>
>> perf.data file contains different types of sample event.
>>
>> If the same IP sample event exists in branch-misses and branch-instructions,
>> this event uses the same symbol. When annotate branch-misses events, notes->src
>> corresponding to this event is set to null, as a result, when annotate
>> branch-instructions events, this event is skipped and no annotate is output.
>>
>> Solution of this patch is to remove zfree in hists__find_annotations and
>> change sort order to "dso,symbol" to avoid duplicate output when different
>> processes correspond to the same symbol.
> 
> You forgot to add your Signed-off-by tag, i.e.:
> 
> Signed-off-by: Yang Jihong <yangjihong1@...wei.com>
> 
> Please take a look at Documentation/process/submitting-patches.rst.
> 
> Regards,
> 
> - Arnaldo
> 
Thanks for the patient instructions :)
I've submitted the v6 patch, look forward to your review:
https://lore.kernel.org/patchwork/patch/1397675

>> ---
>>   tools/perf/builtin-annotate.c | 13 ++++++-------
>>   1 file changed, 6 insertions(+), 7 deletions(-)
>>
>> diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
>> index a23ba6bb99b6..92c55f292c11 100644
>> --- a/tools/perf/builtin-annotate.c
>> +++ b/tools/perf/builtin-annotate.c
>> @@ -374,13 +374,6 @@ static void hists__find_annotations(struct hists *hists,
>>   		} else {
>>   			hist_entry__tty_annotate(he, evsel, ann);
>>   			nd = rb_next(nd);
>> -			/*
>> -			 * Since we have a hist_entry per IP for the same
>> -			 * symbol, free he->ms.sym->src to signal we already
>> -			 * processed this symbol.
>> -			 */
>> -			zfree(&notes->src->cycles_hist);
>> -			zfree(&notes->src);
>>   		}
>>   	}
>>   }
>> @@ -619,6 +612,12 @@ int cmd_annotate(int argc, const char **argv)
>>   
>>   	setup_browser(true);
>>   
>> +	/*
>> +	 * Events of different processes may correspond to the same
>> +	 * symbol, we do not care about the processes in annotate,
>> +	 * set sort order to avoid repeated output.
>> +	 */
>> +	sort_order = "dso,symbol";
>>   	if ((use_browser == 1 || annotate.use_stdio2) && annotate.has_br_stack) {
>>   		sort__mode = SORT_MODE__BRANCH;
>>   		if (setup_sorting(annotate.session->evlist) < 0)
>> -- 
>> 2.30.GIT
>>
>